U.S. patent application number 17/012899 was filed with the patent office on 2020-12-24 for printing rubber blanket and manufacturing method of the same.
The applicant listed for this patent is KINYOSHA CO., LTD.. Invention is credited to Masakuni KAWAGUCHI, Ryuta TANAKA.
Application Number | 20200398601 17/012899 |
Document ID | / |
Family ID | 1000005077823 |
Filed Date | 2020-12-24 |
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United States Patent
Application |
20200398601 |
Kind Code |
A1 |
TANAKA; Ryuta ; et
al. |
December 24, 2020 |
PRINTING RUBBER BLANKET AND MANUFACTURING METHOD OF THE SAME
Abstract
A printing rubber blanket includes base layer, a surface rubber
layer provided on one surface of the base layer and metal layer
provided on the other surface of the base layer on the opposite
side of the surface rubber layer. The metal layer includes a
passivation layer on at least a surface thereof on the opposite
side of the base layer.
Inventors: |
TANAKA; Ryuta;
(Tsuchiura-shi, JP) ; KAWAGUCHI; Masakuni;
(Hitachinaka-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KINYOSHA CO., LTD. |
Tokyo |
|
JP |
|
|
Family ID: |
1000005077823 |
Appl. No.: |
17/012899 |
Filed: |
September 4, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2018/044979 |
Dec 6, 2018 |
|
|
|
17012899 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B32B 7/12 20130101; B41N
2210/06 20130101; B32B 15/06 20130101; B41N 2210/02 20130101; B32B
15/18 20130101; B41N 10/04 20130101; B41N 2210/04 20130101; B32B
15/08 20130101 |
International
Class: |
B41N 10/04 20060101
B41N010/04; B32B 7/12 20060101 B32B007/12; B32B 15/08 20060101
B32B015/08; B32B 15/06 20060101 B32B015/06; B32B 15/18 20060101
B32B015/18 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 6, 2018 |
JP |
2018-039998 |
Claims
1. A printing rubber blanket comprising: a base layer; a surface
rubber layer provided on one surface of the base layer; and a metal
layer provided on the other surface of the base layer on the
opposite side of the surface rubber layer, wherein the metal layer
includes a passivation layer on at least a surface thereof on the
opposite side of the base layer.
2. The blanket of claim 1, wherein a thickness of the passivation
layer is 5 nm to 2 .mu.m.
3. The blanket of claim 1, wherein the metal layer is constituted
of stainless steel.
4. The blanket of claim 1, wherein the metal layer further includes
a polymer layer on a surface of the passivation layer.
5. The blanket of claim 1, wherein the metal layer further includes
a second passivation layer on a surface thereof on the base layer
side.
6. A manufacturing method of a printing rubber blanket comprising:
a step of subjecting at least one surface of metallic foil to
chemical conversion treatment to thereby form a passivation layer;
a step of preparing a rubber blanket piece including a base layer
and a surface rubber layer; and a step of bonding a surface of the
metallic foil on the opposite side of the passivation layer and a
surface of the rubber blanket piece on the base layer side to each
other.
7. The method of claim 6, wherein a thickness of the passivation
layer is 5 nm to 2 .mu.m.
8. The method of claim 6, wherein the metallic foil is constituted
of stainless steel.
9. The method of claim 6, further comprising a step of forming a
polymer layer on a surface of the passivation layer of the metallic
foil.
10. The method of claim 6, further comprising a step of forming a
second passivation layer on a surface of the metallic foil to be
bonded to the base layer.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation Application of PCT
Application No. PCT/JP2018/044979, filed Dec. 6, 2018 and based
upon and claiming the benefit of priority from prior Japanese
Patent Application No. 2018-039998, filed Mar. 6, 2018, the entire
contents of all of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The present invention relates to a printing rubber blanket
used for offset printing and manufacturing method thereof.
2. Description of the Related Art
[0003] A rubber blanket used for offset printing is generally
provided with a base layer including a plurality of base textiles
and sponge rubber layer (compressible rubber layer) and surface
rubber layer formed on the base layer. Such a rubber blanket is
used by being wrapped around a blanket cylinder with the surface
rubber layer being outside. Due to long-time use of the rubber
blanket, the stress of the base textiles is loosened up whereby
slackness of the base textiles is caused or the base textiles
elongate to reduce the thickness. Accordingly, there has been a
problem in that it becomes impossible to carry out stable
printing.
[0004] As a method of maintaining the tension or thickness of the
rubber blanket constant during the period of endurance, a method
using a rubber blanket provided with metallic foil on a surface
thereof coming into contact with a blanket cylinder (hereinafter
referred to also as a "metal-backed blanket") is disclosed in JP
H03-133695 A. However, in this configuration, there is a problem in
that the metallic foil or blanket cylinder is corroded by washing
to be carried out during the printing process or after printing.
The corrosion is attributable to the fact that the cleaning liquid
enters a part between the metallic foil and blanket cylinder and a
chemical substance contained in the cleaning liquid acts as an
electrolyte to thereby cause the metallic foil and blanket cylinder
constituted of metals different from each other in the ionization
tendency to bring about a corrosion reaction. Moreover, in this
configuration, there is a problem in that the metallic foil and
blanket cylinder rub against each other to cause abrasion.
[0005] As a solution to such a problem, a metal-backed blanket
provided with an insulator (for example, Mylar (registered trade
mark)) or the like on the surface of the metallic foil on the
blanket cylinder side in order that the metallic foil and blanket
cylinder may not come into direct contact with each other is used.
Further, in JP 4388476 B, a rubber blanket in which a polymer layer
is formed on a surface of the metallic foil on the blanket cylinder
side is disclosed. In JP 2010-532723 A, a rubber blanket provided
with a plastic film on a surface of the metallic foil on the
blanket cylinder side is disclosed. According to these methods, the
metallic foil and blanket cylinder are prevented from coming into
direct contact with each other.
BRIEF SUMMARY OF THE INVENTION
[0006] However, the metal-backed blanket provided with an insulator
has a problem in that the adhesion layer is dissolved in the
cleaning agent whereby the insulator exfoliates from the metallic
foil. At the part of occurrence of the exfoliation, the thickness
of the blanket changes, and hence a defect in printing occurs.
Further, in the metal-backed blanket provided with a polymer layer
on the surface thereof, there is a problem in that the adhesive
strength between the metallic foil and polymer layer is
insufficient, and hence the polymer layer exfoliates or separates
from the metallic foil at the time of printing. Such an operation
as to damage the polymer layer in handling the blanket, for
example, rubbing the polymer layer with the surface of the working
table particularly causes the exfoliation or separation. At the
part of occurrence of the exfoliation or separation of the polymer
layer, the metallic foil and blanket cylinder come into direct
contact with each other, and hence corrosion is thereby caused.
Furthermore, also in an example in which a plastic film is bonded
to the metallic foil by thermal adhesion, there is a problem in
that the plastic film exfoliates during use.
[0007] An embodiment described herein aims to provide a printing
rubber blanket preventing corrosion and abrasion of the metallic
foil and blanket cylinder from occurring and manufacturing method
thereof.
[0008] A printing rubber blanket according to an embodiment is
provided with a base layer, surface rubber layer formed on one
surface of the base layer, and metal layer formed on the other
surface of the base layer on the opposite side of the surface
rubber layer. The metal layer includes a passivation layer on at
least a surface thereof on the opposite side of the base layer
side.
[0009] According to the embodiment, it is possible to provide a
printing rubber blanket making it possible to prevent corrosion and
abrasion of the metallic foil and blanket cylinder from occurring
and enabling stable printing and manufacturing method thereof.
[0010] Additional objects and advantages of the invention will be
set forth in the description which follows, and in part will be
obvious from the description, or may be learned by practice of the
invention. The objects and advantages of the invention may be
realized and obtained by means of the instrumentalities and
combinations particularly pointed out hereinafter.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0011] The accompanying drawings, which are incorporated in and
constitute a part of the specification, illustrate embodiments of
the invention, and together with the general description given
above and the detailed description of the embodiments given below,
serve to explain the principles of the invention.
[0012] FIG. 1 is a schematic view showing a printing rubber blanket
according to an embodiment.
[0013] FIG. 2 is a schematic view showing a printing rubber blanket
according to the embodiment.
[0014] FIG. 3 is a schematic view showing a printing rubber blanket
according to the embodiment.
[0015] FIG. 4 is a flowchart showing a manufacturing method of the
printing rubber blanket according to the embodiment.
[0016] FIG. 5A is a schematic view showing a state where the
printing rubber blanket according to the embodiment is attached to
the blanket cylinder.
[0017] FIG. 5B is a schematic view showing a state where the
printing rubber blanket according to the embodiment is fixed to the
blanket cylinder.
[0018] FIG. 5C is an enlarged view obtained by enlarging the part
of FIG. 5B surrounded by a dotted line C.
DETAILED DESCRIPTION OF THE INVENTION
[0019] Hereinafter, an embodiment of the present invention will be
described with reference to the accompanying drawings. The drawings
are schematic views and the scales on which the drawings are
prepared are not accurate. It should be noted that, in the
following description, a surface on the upper side of each layer is
described as a "top surface" and surface on the underside is
described as an "undersurface" according to the arrangement of FIG.
1.
[0020] FIG. 1 is a schematic view showing a printing rubber blanket
according to the embodiment. The printing rubber blanket 1 is
provided with a base layer 2, surface rubber layer 3, and metal
layer 4. The surface rubber layer 3 is provided on the top surface
of the base layer 2. The metal layer 4 is provided on the
undersurface of the base layer 2. The metal layer 4 is provided
with a passivation layer 9 on the undersurface 8 thereof.
Hereinafter, each configuration will be described in detail.
[0021] The base layer 2 is a layer configured to support thereon
the surface rubber layer 3. The base layer 2 is provided with, for
example, a base textile layer 5, compressible rubber layer 6, and
reinforcing textile 7.
[0022] The base textile layer 5 is provided with, for example,
three base textiles 5a, 5b, and 5c. The base textile 5a and base
textile 5b are bonded to each other with a rubber layer 5d. The
base textile 5b and base textile 5c are bonded to each other with a
rubber layer 5e. Although in this example, the base textile layer 5
is provided with the three base textiles, the number of base
textiles may be one or two, or four or more base textiles may also
be used.
[0023] As the base textiles 5a, 5b, and 5c, a base textile
generally used for a printing rubber blanket can be used. The base
textile is constituted of, for example, woven cloth, nonwoven cloth
or a combination of any of these or the like. The woven cloth and
nonwoven cloth can be formed of fiber including, for example,
cotton, wool, linen, silk, rayon, cupro, acetate, nylon, vinylon,
polyester, polyvinyl chloride, acrylic, acrylate, polyimide, carbon
fiber, aramid fiber, glass fiber or a combination of any of these
or the like. Although the contexture of the base textile is not
specifically limited, plain weave, twill weave, sateen weave, and
the like are named as the contexture.
[0024] As the rubber layers 5d and 5e, a rubber material generally
used for a printing rubber blanket can be used. Although the rubber
material is not specifically limited, for example,
acrylonitrile-butadiene rubber, chloroprene rubber, fluororubber,
polyurethane rubber, ethylene-propylene rubber, butyl rubber or a
combination of any of these or the like can be named as the rubber
material.
[0025] The compressible rubber layer 6 is a layer having cushioning
characteristics provided on the top surface of the base textile
layer 5. As the compressible rubber layer 6, a compressible rubber
layer generally used for a printing blanket can be used. Although
the compressible rubber layer 6 is not specifically limited, sponge
rubber constituted of, for example, acrylonitrile-butadiene rubber,
chloroprene rubber, fluororubber, polyurethane rubber,
ethylene-propylene rubber, butyl rubber or a combination of any of
these or the like can be used as the compressible rubber 6. It is
desirable that the thickness of the compressible rubber layer 6 be,
for example, greater than or equal to 0.1 mm and less than or equal
to 2.0 mm.
[0026] The reinforcing textile 7 is a textile provided on the top
surface of the compressible rubber layer 6 and configured to
reinforce the base layer 2. As the reinforcing textile 7, for
example, any one of the abovementioned base textiles may be
used.
[0027] The base layer 2 may include a layer constituted of a
further material in addition to the abovementioned configuration.
Such a layer is, for example, a reinforcing layer, further bonding
layer, further compressible rubber layer, layer or the like
constituted of a further textile. It is desirable that the
thickness of the whole base layer 2 be 500 to 3000 .mu.m.
[0028] The surface rubber layer 3 is provided on the surface (top
surface of the reinforcing textile 7 in the example of FIG. 1) of
the base layer 2. As the material for the surface rubber layer 3, a
material generally used for a printing blanket can be used.
Although the material for the surface rubber layer 3 is not
specifically limited, for example, nitrile rubber, natural rubber,
styrene-butadiene rubber, chloroprene, butyl rubber,
ethylene-propylene rubber, chlorosulfonated polyethylene, silicone
rubber, fluororubber or a combination of any of these or the like
is named as the material for the surface rubber layer 3. It is
desirable that the thickness of the surface rubber layer 3 be, for
example, 0.2 to 0.5 mm. For example, the surface rubber layer 3 may
be bonded to the reinforcing textile 7 with any one of the
abovementioned rubber materials or the like.
[0029] The base layer 2 and surface rubber layer 3 are not limited
to the aforementioned configurations, and the base layer 2 and
surface rubber layer 3 may have configurations of a base layer and
surface rubber layer used in a general printing rubber blanket.
[0030] The metal layer 4 is a thin plate-like metal provided on the
undersurface of the base layer 2. The metal layer is hereinafter
referred to also as metallic foil. The material for the metal layer
4 is, for example, a metal capable of forming a passivation layer
9. As the material for the metal layer 4, iron, nickel, aluminum,
chromium, titanium or the like or an alloy or the like containing
any one of these can be used. The alloy is, for example, stainless
steel. It is desirable that, particularly from the viewpoint of
cost, and a high degree of strength, stainless steel, for example,
steel special use stainless (SUS) be used.
[0031] It is desirable that the thickness of the metal layer 4 be,
for example, 0.10 to 0.30 mm.
[0032] The metal layer 4 is provided with a passivation layer 9 on
at least the undersurface 8 thereof. The passivation layer 9 is
constituted of, for example, an oxide of a metal contained in the
material for the metal layer 4. The passivation layer 9 has, for
example, the composition identical to the oxide film of the
material for the metal layer 4. For example, when the metal layer 4
is constituted of SUS, the passivation layer 9 is constituted of an
oxide of chromium having hydrated chromium oxyhydroxide
(CrO.sub.x(OH).sub.2-x.nH.sub.2O) or the like as the main
component.
[0033] The thickness of the passivation layer 9 is thicker than the
passive oxide film naturally formed on the metal layer 4. The
thickness of the passivation layer 9 is, for example, 5 nm to 2
.mu.m. It is more desirable that the thickness be 10 to 100 nm.
When the thickness of the passivation layer 9 is greater than or
equal to 5 nm, the metal layer 4 and blanket cylinder can be
prevented from causing a corrosion reaction. Further, in view of
cost in the manufacture, it is desirable that the thickness of the
passivation layer 9 be less than or equal to 2 .mu.m.
[0034] The metal layer 4 may further be provided with a passivation
layer on the top surface thereof. Such an example is shown in FIG.
2. In this example, the metal layer 4 is provided with a first
passivation layer 9a and second passivation layer 9b on the
undersurface 8a and top surface 8b thereof. The metal layer 4 is
provided with the second passivation layer 9b on the top surface 8b
thereof, whereby the adhesive strength between the metal layer 4
and base layer 2 is enhanced. Thereby, it is possible to prevent
the metal layer 4 from exfoliating from the base layer 2 while the
printing rubber blanket 1 is used. Furthermore, a passivation layer
9 may be provided on the side face of the metal layer 4.
[0035] The top surface of the metal layer 4 is bonded to the
undersurface of the base layer 2 with an adhesive. As the adhesive,
for example, a thermosetting adhesive, thermoplastic adhesive or
the like can be used. The metal layer 4 may be configured longer
than the base layer 2 and surface rubber layer 3 and end of the
printing rubber blanket 1 may be constituted of only the metal
layer 4. The end of the printing rubber blanket 1 constituted of
only the metal layer 4 may be, for example, the fitting section to
be fixed to the blanket cylinder when the printing rubber blanket 1
is attached to the blanket cylinder.
[0036] The printing rubber blanket 1 has a desired size according
to the use application. Although it is desirable that for example,
the width be 100 to 1200 mm, length be 100 to 1200 mm, and
thickness be 0.8 to 4.0 mm or the like, the dimensions are not
limited to these.
[0037] The printing rubber blanket according to the embodiment
described above includes the passivation layer 9 on the
undersurface of the metal layer 4. The passivation layer 9 is
thicker than a passive oxide film naturally formed on the metal
layer 4. Such a passivation layer 9 is never ruined under the
condition of coexistence of the chemical substance contained in the
cleaning agent and acting as an electrolyte, metal layer 4, and
blanket cylinder with each other. Accordingly, it is possible to
prevent the metal layer 4 and blanket cylinder from causing a
corrosion reaction. As a result, it is possible to prevent
corrosion (for example, rusting) from occurring and carry out
printing during the period of endurance of the printing rubber
blanket. Further, the passivation layer 9 never exfoliates, and
hence it is possible to maintain the thickness of the blanket
constant during the period of endurance. Moreover, by virtue of the
existence of the passivation layer 9, it is possible to prevent
abrasion of the metal layer 4 from occurring. Therefore, according
to the printing blanket according to the embodiment, it is possible
to stably carry out excellent printing.
[0038] A further embodiment will be described below by using FIG.
3. The printing rubber blanket 1 of this example is provided with a
polymer layer 10 on the undersurface of the passivation layer 9 of
the metal layer 4.
[0039] It is desirable that the material for the polymer layer 10
be, for example, an acrylic resin, epoxy resin, fluororesin or a
combination of any of these or the like. Alternatively, as the
polymer layer 10, a melamine resin, phenolic resin or the like may
be used. Alternatively, the material for the polymer layer 10 may
be a polyamide, polyester, polypropylene, polyethylene,
polyurethane, polyolefin, phenolic compound, nylon polyvinyl
fluoride, copolymer including polyvinyl chloride or polyvinyl
acetate, or ethylene-acrylic acid, ethylene-methacrylic acid
copolymer or the like. The material for the polymer layer 10 may
further be ionomer, acid denaturation polymer, anhydride
denaturation polymer or the like.
[0040] It is desirable that the thickness of the polymer layer 10
be 5 to 250 .mu.m. It is more desirable that the thickness of the
polymer layer 10 be 5 to 20 .mu.m. The polymer layer 10 has such a
desirable thickness, whereby it is possible for the printing rubber
blanket 1 to have an appropriate thickness as a whole, and it is
possible for the polymer layer 10 to have sufficient durability.
Further, in view of manufacturing cost, and risk in case of most
unlikely falling off, the thickness of the polymer layer 10 is
desirably about 5 to 20 .mu.m.
[0041] The passivation layer 9 is provided on the undersurface 8 of
the metal layer 4, whereby the adhesion strength between the
polymer layer 10 and metal layer 4 is enhanced. Accordingly, the
polymer layer 10 is prevented from exfoliating from the metal layer
4. Further, by providing the polymer layer 10, the metal layer 4 is
protected, and corrosion (rusting) and abrasion of the metal layer
4 and blanket cylinder can further be prevented from occurring.
[0042] Next, the manufacturing method of the printing rubber
blanket 1 will be described below.
[0043] FIG. 4 is a schematic flowchart showing an example of the
manufacturing method of the printing rubber blanket according to
the embodiment. The manufacturing method of the printing rubber
blanket 1 includes the following steps (S1) to (S3). Step of
subjecting at least one surface of the metallic foil to chemical
conversion treatment to thereby form a passivation layer (S1). Step
of preparing a rubber blanket piece provided with a base layer and
surface rubber layer (S2). Step of bonding a surface of the
metallic foil on the opposite side of the passivation layer and
surface of the rubber blanket piece on the base layer side to each
other (S3).
[0044] Hereinafter, the steps will be described in detail.
[0045] In step (S1), a passivation layer is formed on the metallic
foil. As the metallic foil, any one of the aforementioned metal
layers or types of metallic foil can be used. The passivation layer
is formed by subjecting one surface of the metallic foil to
chemical conversion treatment. The chemical conversion treatment
is, for example, passivation treatment, chromate conversion
treatment, phosphatizing treatment, gunblue treatment, other
chemical conversion treatment or the like. For example, when the
metal layer is constituted of SUS, it is desirable that formation
of the passivation layer be carried out by passivation treatment,
chromate conversion treatment or zirconium-based chemical
conversion treatment.
[0046] The abovementioned chemical conversion treatment can be
carried out by, for example, a general method used in the chemical
conversion treatment of a metal. The chemical conversion treatment
can be carried out by, for example, immersing the surface of the
metallic foil to be subjected to the chemical conversion treatment
in a solution containing a chemical agent to be used for the
chemical conversion treatment (hereinafter referred to as the
chemical conversion treatment agent) or subjecting the surface of
the metallic foil to electrolysis in a solution containing the
chemical conversion treatment agent or applying the chemical
conversion treatment agent to a desired surface of the metallic
foil, or the like. For example, when the metal layer is constituted
of SUS, the passivation layer can be formed by immersing the
desired surface of the SUS plate in a potassium dichromate
solution, sodium sulfate solution, concentrated nitric acid or the
like or applying the abovementioned solution to the desired surface
of the metallic foil and drying the applied solution.
[0047] The thickness of the passivation layer is formed thicker
than a passive oxide film naturally formed on the metal layer. For
example, it is desirable that the passivation layer be formed in
such a manner as to have a thickness of 5 nm to 2 .mu.m. It is more
desirable that the thickness be 10 to 100 nm. It is possible to
form the passivation layer in such a manner as to have a desired
thickness by, for example, adjusting the period of time during
which the metallic foil is made in contact with the chemical
conversion treatment agent. The thickness of the passivation layer
can be measured by, for example, an ellipsometer or the like.
[0048] The passivation layer may be formed only on the undersurface
of the metallic foil or a second passivation layer may further be
formed on the top surface thereof. Furthermore, a passivation layer
may be formed on the side face of the metallic foil.
[0049] When a polymer layer is formed on the surface of the
metallic foil on which the passivation layer is formed, it is
sufficient if, after the passivation layer is formed on the
metallic foil, a polymer layer is formed on the undersurface of the
metallic foil by any known polymer coating method. As the polymer
coating method, for example, blade coating, spray coat, dipping,
electrostatic coating method, roll coat method or the like can be
used.
[0050] In step (S2), a rubber blanket piece provided with the base
layer and surface rubber layer is prepared. Here, the surface
rubber layer is provided on the base layer. As the rubber blanket
piece, any one of the abovementioned base layers and surface rubber
layers can be used.
[0051] Regarding step (S1) and step (S2), any one of them may be
carried out first.
[0052] In step (S3), the surface of the metal layer on the opposite
side of the passivation layer and surface of the blanket piece on
the base layer side are bonded to each other. Bonding is carried
out by using, for example, a thermosetting adhesive, thermoplastic
adhesive or the like. BY carrying out the abovementioned steps, the
printing rubber blanket according to the embodiment can be
manufactured. The example of the manufacturing method of the
printing rubber blanket is constituted only of steps (S1) to (S3)
described above.
[0053] The printing rubber blanket according to the embodiment is
used by being attached to the blanket cylinder. Hereinafter, an
example of the method of using the printing rubber blanket will be
described.
[0054] FIG. 5A to FIG. 5C are cross-sectional views showing an
example of a blanket cylinder 20 in a state where the blanket
cylinder 20 is mounted with the printing rubber blanket 1. FIG. 5A
and FIG. 5B are cross-sectional views obtained by cutting the
blanket cylinder 20 perpendicularly to the longitudinal direction
thereof. FIG. 5A shows a state where the printing rubber blanket 1
is being attached to the blanket cylinder 20. FIG. 5B shows a state
where the printing rubber blanket 1 is fixed to the blanket
cylinder 20 by way of the state of FIG. 5A. FIG. 5C is an enlarged
view obtained by enlarging the part of FIG. 5B surrounded by a
dotted line C.
[0055] The blanket cylinder 20 is provided with a columnar cylinder
main body 21 and shaft section 22 serving as a shaft configured to
rotate the cylinder main body 21. A gap 23 is formed in a surface
of the cylinder main body 21. The gap 23 is opened from the surface
of the cylinder main body 21 to the inside of the cylinder main
body 21. A blanket fixing mechanism 24 is arranged inside the
cylinder main body 21. The blanket fixing mechanism 24 is provided
with two fixing shafts (first fixing shaft 25a and second fixing
shaft 25b). The first fixing shaft 25a is provided with a first
gripper section 26a configured to fix one end (gripper side edge)
of the printing rubber blanket 1. The second fixing shaft 25b is
provided with a second gripper section 26b configured to fix the
other end (gripper end side edge) of the printing rubber blanket
1.
[0056] Fixing of the printing rubber blanket 1 to the cylinder main
body 21 is carried out in the following manner. First, the metal
layer 4 serving as the gripper side edge of the printing rubber
blanket 1 is inserted into the gap 23 with the surface thereof
having the surface rubber layer 3 facing upward to thereby be set
to the first gripper section 26a. Thereafter, the metal layer 4
serving as the gripper end side edge of the printing rubber blanket
1 is inserted into the gap 23 by way of the circumferential surface
of the cylinder main body 21 to thereby be set to the second
gripper section 26b (FIG. 5A).
[0057] Next, by rotating the second fixing shaft 25b, the leading
end of the second gripper section 26b is pressed against the side
face of the first gripper section 26a (FIG. 5B). Thereby, the
printing rubber blanket 1 is fixed to the cylinder main body
21.
[0058] As shown in FIG. 5C, a seal section 28 may be provided in
such a manner as to couple the ends of the base layer 2 and surface
rubber layer 3 to the bent section 27 of the metal layer 4. By
virtue of the seal section 28, the base layer 2 and surface rubber
layer 3 are prevented from peeling off the metal layer 4 while the
printing rubber blanket 1 is used.
[0059] The method of using the printing rubber blanket 1 is not
limited to the method described above. For example, the printing
rubber blanket 1 can be used by being attached to any blanket
cylinder generally used for offset printing.
EXAMPLE
[0060] Examples of investigating presence/absence of exfoliation of
the blanket according to the embodiment, presence/absence of
corrosion of the metallic foil, presence/absence of corrosion of
the blanket cylinder, and printability (suitability for printing)
are shown below.
[0061] Preparation of Printing Rubber Blanket A rubber blanket
piece configured in such a manner that a base layer including four
base textiles, compressible rubber layer, reinforcing textile, and
surface rubber layer (thickness 0.5 mm) are bonded to each other in
the order mentioned was prepared. The abovementioned rubber blanket
piece was used to produce nine types of printing rubber blankets of
the following examples 1 to 3 and comparative examples 1 to 6.
Example 1: Passivation Layer Only
[0062] A passivation layer of a thickness of 5 nm was formed on one
surface of the metallic foil of SUS having a thickness of 200 .mu.m
by subjecting the surface to passivation treatment. The thickness
of the passivation layer was measured by using a visible
spectrophotometric ellipsometer Smart SE (made by HORIBA, Ltd.). A
printing rubber blanket was produced by bonding the surface of the
metallic foil on the opposite side of the passivation layer to the
surface of the rubber blanket piece on the base layer side.
Example 2: Passivation Layer+Epoxy Resin
[0063] The passivation layer surface of the metallic foil of the
printing rubber blanket identical to the example 1 was coated with
an epoxy resin of a thickness of 10 .mu.m.
Example 3: Passivation Layer+Acrylic Resin
[0064] The passivation layer surface of the metallic foil of the
printing rubber blanket identical to the example 1 was coated with
an acrylic resin of a thickness of 10 .mu.m.
Comparative Example 1: No Passivation Layer+Polyester Film
[0065] One surface of a polyester film having a thickness of 0.125
mm was coated with an adhesive with a thickness of 0.035 mm. This
polyester film was stuck to one surface of SUS metallic foil of a
thickness of 0.175 mm which has not been subjected to chemical
conversion treatment by thermal adhesion. The other surface of the
metallic foil on the opposite side of the film side was bonded to
the surface of the rubber blanket piece on the base layer side.
Comparative Example 2: No Passivation Layer+Polyimide Film
[0066] One surface of a polyimide film having a thickness of 0.125
mm was coated with an adhesive with a thickness of 0.035 mm. This
polyimide film was stuck to one surface of SUS metallic foil of a
thickness of 0.175 mm which has not been subjected to chemical
conversion treatment by thermal adhesion. The other surface of the
metallic foil on the opposite side of the film side was bonded to
the surface of the rubber blanket piece on the base layer side.
Comparative Example 3: No Passivation Layer+Polyamide Film
[0067] One surface of a polyamide film having a thickness of 0.125
mm was coated with an adhesive with a thickness of 0.035 mm. This
polyamide film was stuck to one surface of SUS metallic foil of a
thickness of 0.175 mm which has not been subjected to chemical
conversion treatment by thermal adhesion. The other surface of the
metallic foil on the opposite side of the film side was bonded to
the surface of the rubber blanket piece on the base layer side.
Comparative Example 4: No Passivation Layer
[0068] One surface of SUS metallic foil of a thickness of 0.175 mm
which has not been subjected to chemical conversion treatment was
bonded to the surface of the rubber blanket piece on the base layer
side.
Comparative Example 5: No Passivation Layer+Epoxy Resin
[0069] One surface of SUS metallic foil of a thickness of 0.175 mm
which has not been subjected to chemical conversion treatment was
coated with an epoxy resin with a thickness of 10 .mu.m. The
surface of the metallic foil on the opposite side of the resin side
was bonded to the surface of the rubber blanket piece on the base
layer side.
Comparative Example 6: No Passivation Layer+Acrylic Resin
[0070] One surface of SUS metallic foil of a thickness of 0.175 mm
which has not been subjected to chemical conversion treatment was
coated with an acrylic resin with a thickness of 10 .mu.m. The
surface of the metallic foil on the opposite side of the resin side
was bonded to the surface of the rubber blanket piece on the base
layer side.
[0071] Evaluation of Presence/Absence of Exfoliation,
Presence/Absence of Corrosion of Metallic Foil, and
Presence/Absence of Corrosion of Blanket Cylinder
[0072] Each of the blankets of the examples 1 to 3 and comparative
examples 1 to 6 described above was attached to a blanket cylinder
and was rotated 10,000,000 times at a rotational speed of 1,000 rpm
under printing pressure of 0.2 mm. A cleaning liquid was made to
flow along the surface of the blanket and between the blanket and
blanket cylinder at a frequency of once per 500,000 revolutions,
whereby the state of cleaning and residence of the cleaning liquid
in the normal use was reproduced.
[0073] Thereafter, evaluations were carried out with respect to
presence/absence of exfoliation, presence/absence of corrosion of
the metallic foil, and presence/absence of corrosion of the blanket
cylinder.
[0074] Evaluation of Printability (Suitability for Printing) of
Printing Rubber Blankets
[0075] Each of the blankets of the examples 1 to 3 and comparative
examples 1 to 6 was used to carry out printing by using the actual
machine and the printability was evaluated. Regarding the
conditions of printing by the actual machine, the push-in amount
was 0.2 mm, speed was 60,000 copies/h, and number of printed copies
was 5,000. When deterioration in printing quality such as omission,
blurring or the like was found in printing, the printability was
judged to be "bad" and, when no deterioration in printing quality
was found, the printability was judged to be "good". The results of
the evaluations of all the examples and comparative examples are
summarized in Tables 1 and 2.
TABLE-US-00001 TABLE 1 Metallic Blanket Configuration foil cylinder
of metal layer Exfoliation corrosion corrosion Printability Example
Passivation layer -- None None Good 1 Example Passivation layer +
None None None Good 2 epoxy resin Example Passivation layer + None
None None Good 3 acrylic resin
TABLE-US-00002 TABLE 2 Metallic Blanket Configuration foil cylinder
of metal layer Exfoliation corrosion corrosion Printability
Comparative Polyester film Found None None Bad example 1
Comparative Polyimide film Found None None Bad example 2
Comparative Polyamide film Found None None Bad example 3
Comparative No working -- Found Found Good example 4 Comparative
Epoxy resin Found Found Found Good example 5 Comparative Acrylic
resin Found Found Found Good example 6
[0076] In the examples 1 to 3, exfoliation of resin and corrosion
did not occur. Further, the printability was good in the examples 1
to 3. On the other hand, in the comparative examples 1 to 3,
although corrosion did not occur in the metallic foil, exfoliation
occurred in the film. Therefore, the printability was judged to be
bad. In the comparative example 4, although the printability was
good, corrosion occurred in the metallic foil. In the comparative
examples 5 and 6, although the printability was good, exfoliation
of the resin occurred and corrosion occurred in the metallic
foil.
[0077] From the results described above, according to the printing
rubber blanket according to the embodiment, it has become clear
that it is possible to prevent corrosion and abrasion of the
metallic foil and blanket cylinder from occurring.
[0078] Additional advantages and modifications will readily occur
to those skilled in the art. Therefore, the invention in its
broader aspects is not limited to the specific details and
representative embodiments shown and described herein. Accordingly,
various modifications may be made without departing from the spirit
or scope of the general inventive concept as defined by the
appended claims and their equivalents.
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